OBJECTIVE To determine if the restriction of dietary caloric intake (without malnutrition) can retard the rate of aging in a primates. RESULTS Dietary restriction (DR) is being widely investigated in gerontology because only DR retards the rate of aging in rodents. Whether DR retards aging in primates is unknown. We hypothesize that DR influences aging processes in primates like it does in rodents and that this influence is reflected by an altered rate of change of certain physiologic parameters of aging. We aim to 1) contribute to developing the rhesus monkey as a model for studies of aging, and 2) determine the influence of DR on the rate of aging in a primate species. To date, we have found that DR (a 30% reduction in calorie intake) can be safely imposed on rhesus monkeys. Further, there are indications that the restricted monkeys are in better health (e.g., better glucoregulation, less arthritis, favorable changes in plasma lipids) than age-matched controls. FUTURE DIRECTIONS A five-year competitive renewal application for the Program Project was submitted to NIA on February 1, 1998. A revised application was submitted on October 1, 1998, which is still pending. KEY WORDS food intake, dietary restriction, caloric restriction, aging FUNDING NIH AG11915 PUBLICATIONS Edwards IJ, Rudel LL, Terry JG, Kemnitz JW, Weindruch R, Cefalu WT Caloric restriction in rhesus monkeys reduces low density lipoprotein interaction with arterial proteoglycans. J. Gerontol. Biol. Sci. 53A:B443-448, 1998. Lee CM, Lopez ME, Weindruch R, Aiken JM Association of age-related mitochondrial abnormalities with skeletal muscle fiber atrophy. Free Radic. Biol. Med. 25:964-972, 1998.